Following typical Catalyst applications are being proposed: for selective hydrogenation, Isomerization, aromatic saturation and Hydrodesulfurization of Gasoline, kerosene and Diesel/distillates. The invention's advantages can be easily seen by people familiar in art and the merits of different catalyst for different applications but are not limited to these catalysts only. The art also allows the user to switch catalyst based on the availability in the market place if some new catalyst comes to the market; the information provided here is just for illustration. The processes/configurations use different catalyst for Selective Hydrogenation and isomerization, hydrodesulfurization, aromatic saturation and also for desulfurization of cracked and straight run Feeds as shown below.
Following catalyst is used for the services proposed in this invention and are not limited to these and can use any commercial available catalyst for the service. The unique and superior configuration provides advantages in selectivity, low cost of catalyst and utilities. Cost of extra equipment is paid up in 6 to 12 months depending on service compared to some technologies which claim lower capital cost. The other advantages of selectivity/Low Octane loss, low energy has been not taken into account for this patent economics as regards to payout period for extra equipment. This essentially means that after taking all the benefits there are major advantages provided by this configuration.
SELECTIVE HydrogenationVinyl acetyleneNi, Ni/W, Ni/Mo, Pd/Ag, Pd/Pt etc.MAPDPd, Pd/Ag, Pd/Pt, Ni, Ni/Mo, Ni/W etc.C4/C5/C6/C7 and LCN or FRCN,Ni, Pd,Diolefin/Sulfur removalNi/Mo, Ni/W, Co/Mo etc.application:Isomerization; Alpha to Beta IsomerizationC4/C5/C6 and LCNPd, Pd/Pt, Pd/Ag, Ni, Ni/Mo and Ni/W.Aromatic HydrogenationBenzene SaturationNi, Pt on Zeolite etcHydrodesulfurizationGasoline HDSNi, Ni/Mo, Co/Mo, Ni/W etc.KerosineNi/Mo, Co/Mo, Ni/W etc.Diesel/DistillateNi/Mo, Co/Mo, Ni/W etcLCO for Cetane improvementZeolite/Pt
As mentioned above that the catalyst could be bulk catalyst from any of the above catalysts but one is not limited to these catalyst only for all the above processes and would chose what ever best catalyst is available in the market. The bulk catalyst in the column or in the side reactors provides high catalyst efficiency and usage and lower catalyst cost and better yield/selectivity and also low utility consumption. There is not much of an advantage of having the catalyst in packaging (which is usually is cumbersome to install/loading) in the column and simultaneous reaction and distillation, except few processes where rate constants are high but that can also be compensated by unique RHT configuration as explained in this and other patents (U.S. Pat. No. 4,503,265). In most of the applications the reaction and distillation operating conditions are not optimum for each unit operation. By artificial means of increasing the certain parameters to make the process workable in this application provides the solution which are not cost effective due much higher and catalyst and operation being at not optimum conditions. RHT provides the application and configuration, with bulk catalyst where both distillation and reaction can be essentially decoupled and run at optimum conditions, but still integrated with the column so as to save the cost. The bulk catalyst in the column or in side reactors attached to column can be loaded above and below the feed location but preferably above the feed location. In some applications the fixed bed reactor can also be installed upstream of the column as shown in the FIGS. 1, 6 and 7. Unless the reaction is very fast and feed rates are small, (specialty chemical application, small equipment), the packaged catalyst and catalyst in baffles/channels could be cumbersome to install through the man way, and is not normal plant design which is convenient and also does not provide the best economics.
Gasoline hydrodesulfurization by Reactive distillation, as per the (U.S. Pat. No. 6,495,030) ICN is taken overhead and is being claimed that that the partial pressure of olefins and H2S is lower hence mercaptan sulfur in the product. On the contrary in Reactive Distillation technology, equilibrium conditions are much favorable at the top to make mercaptan sulfur as the partial pressure of olefins and H2S is highest at the top and also the temperature is lower which favors mercaptan formation. It seems by taking ICN overhead the catalyst bed temperature (WABT) is increased artificially by taking most of the product overhead, this provides temperature required for desulfurization. Though it does the job but at about 1.5 to 2.0 times energy consumption of the conventional process. The Reactive distillation HDS process can heat integrate which makes the unit complex/unstable in operation and by nature the reflux and still energy wastage adds to the energy costs. The catalyst life can be enhanced by running the reactor in two-phase operation rather than vapor phase operation or by selectively hydrogenating the diolefins upstream as suggested in FIGS. 6 and 7.